Been searching around but can't seem to find a decent answer. I have a brand new 2014 forester 4,000miles, went to change the oil for the first time, and as you guessed it i grabbed the CVT drain plug by accident. I probably lost about 1/2 Qt. putting the plug back in.

Should I worry about it?
Or
let it ride till i hit the 7500mile mark and I take it in for it's scheduled maintenance change. I was planning on complaining about the "bucking" action of the CVT at that time anyways to get them to check it...
Or
Stop don't touch it have it towed to the dealership and shell out some ungodly amount to have the dealership check it. My dealer loves to do unnecessary work hence why I do my own routine stuff.

Seeing as most of the plugs have a witness mark placed on them(typically a paint pen, for quality control purposes) on the assembly line. They theoretically could tell someone was in there. I would just own up to it and have the dealer check and adjust the level as needed. I'd call the dealer and see how they want you to get it there(document the call, who, when and where you talked to).

It's under warranty, it isn't worth setting your self up to fail if there is a warranty claim in the future that they could deny for this. The CVT isn't a cheap unit to buy outright, make a standard auto look inexpensive.